#!/usr/bin/python
# coding:utf-8
# auther:DT
# 2017-08-03_11-10-14
a = []
u_name = open("/etc/passwd").readlines()
[a.append(i.split(":")[0]) for i in u_name]
while True:
    s_name =input("please input user name:")

    if s_name in a:
        print("user is exist", s_name)
    elif s_name == "quite":
        break
    else:
        print("user not is exist", s_name)
